Pref service: add support for tracked prefs.

services/preferences/public/cpp/tracked_persistent_pref_store_factory.cc

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "services/preferences/public/cpp/tracked_persistent_pref_store_factory.h"
+
+#include <set>
+#include <utility>
+
+#include "components/prefs/json_pref_store.h"
+#include "components/prefs/pref_filter.h"
+#include "components/user_prefs/tracked/pref_hash_store_impl.h"
+#include "components/user_prefs/tracked/segregated_pref_store.h"
+#include "components/user_prefs/tracked/tracked_preferences_migration.h"
+#include "services/preferences/public/interfaces/tracked_preference_validation_delegate.mojom.h"
+
+#if defined(OS_WIN)
+#include "components/user_prefs/tracked/registry_hash_store_contents_win.h"
+#endif
+
+namespace prefs {
+namespace {
+
+void RemoveValueSilently(const base::WeakPtr<JsonPrefStore> pref_store,
+                         const std::string& key) {
+  if (pref_store) {
+    pref_store->RemoveValueSilently(
+        key, WriteablePrefStore::DEFAULT_PREF_WRITE_FLAGS);
+  }
+}
+
+std::unique_ptr<PrefHashStore> CreatePrefHashStore(
+    const std::string& seed,
+    const std::string& legacy_device_id,
+    bool use_super_mac) {
+  return base::MakeUnique<PrefHashStoreImpl>(seed, legacy_device_id,
+                                             use_super_mac);
+}
+
+std::pair<std::unique_ptr<PrefHashStore>, std::unique_ptr<HashStoreContents>>
+GetExternalVerificationPrefHashStorePair(const std::string& seed,
+                                         const std::string& legacy_device_id,
+                                         const base::string16& registry_path,
+                                         const base::FilePath& prefs_path) {
+#if defined(OS_WIN)
+  return std::make_pair(
+      base::MakeUnique<PrefHashStoreImpl>(seed, legacy_device_id,
+                                          false /* use_super_mac */),
+      base::MakeUnique<RegistryHashStoreContentsWin>(
+          registry_path, prefs_path.DirName().BaseName().LossyDisplayName()));
+#else
+  return std::make_pair(nullptr, nullptr);
+#endif
+}
+
+}  // namespace
+
+PersistentPrefStore* CreateTrackedPersistentPrefStore(
+    scoped_refptr<base::SequencedTaskRunner> io_task_runner,
+    mojom::TrackedPersistentPrefStoreConfigurationPtr config,
+    mojom::TrackedPreferenceValidationDelegate* validation_delegate,
+    const base::Closure& on_reset_on_load) {
+  std::vector<PrefHashFilter::TrackedPreferenceMetadata>
+      unprotected_configuration;
+  std::vector<PrefHashFilter::TrackedPreferenceMetadata>
+      protected_configuration;
+  std::set<std::string> protected_pref_names;
+  std::set<std::string> unprotected_pref_names;
+  for (const auto& metadata : config->tracking_configuration) {
+    PrefHashFilter::TrackedPreferenceMetadata metadata_view = {
+        metadata->reporting_id,      metadata->name.c_str(),
+        metadata->enforcement_level, metadata->strategy,
+        metadata->value_type,
+    };
+    if (metadata->enforcement_level >
+        mojom::TrackedPreferenceMetadata::EnforcementLevel::NO_ENFORCEMENT) {
+      protected_configuration.push_back(metadata_view);
+      protected_pref_names.insert(metadata->name);
+    } else {
+      unprotected_configuration.push_back(metadata_view);
+      unprotected_pref_names.insert(metadata->name);
+    }
+  }
+
+  std::unique_ptr<PrefHashFilter> unprotected_pref_hash_filter(
+      new PrefHashFilter(
+          CreatePrefHashStore(config->seed, config->legacy_device_id, false),
+          GetExternalVerificationPrefHashStorePair(
+              config->seed, config->legacy_device_id, config->registry_path,

[gab, 2017/03/28 16:42:08]

This is the wrong seed, the external hash store uses a separate seed.

This highlights my concern about tweaking this code and enhances my desire for
it to move as-is as much as possible (e.g. can we avoid duplicating
GetExternalVerificationPrefHashStorePair()?)

[Sam McNally, 2017/03/30 09:06:05]

Done.

+              config->unprotected_pref_filename),
+          unprotected_configuration, base::Closure(), validation_delegate,
+          config->reporting_ids_count, false));
+  std::unique_ptr<PrefHashFilter> protected_pref_hash_filter(new PrefHashFilter(
+      CreatePrefHashStore(config->seed, config->legacy_device_id, true),
+      GetExternalVerificationPrefHashStorePair(
+          config->seed, config->legacy_device_id, config->registry_path,
+          config->unprotected_pref_filename),
+      protected_configuration, on_reset_on_load, validation_delegate,
+      config->reporting_ids_count, true));
+
+  PrefHashFilter* raw_unprotected_pref_hash_filter =
+      unprotected_pref_hash_filter.get();
+  PrefHashFilter* raw_protected_pref_hash_filter =
+      protected_pref_hash_filter.get();
+
+  scoped_refptr<JsonPrefStore> unprotected_pref_store(
+      new JsonPrefStore(config->unprotected_pref_filename, io_task_runner.get(),
+                        std::move(unprotected_pref_hash_filter)));
+  scoped_refptr<JsonPrefStore> protected_pref_store(
+      new JsonPrefStore(config->protected_pref_filename, io_task_runner.get(),
+                        std::move(protected_pref_hash_filter)));
+
+  SetupTrackedPreferencesMigration(
+      unprotected_pref_names, protected_pref_names,
+      base::Bind(&RemoveValueSilently, unprotected_pref_store->AsWeakPtr()),
+      base::Bind(&RemoveValueSilently, protected_pref_store->AsWeakPtr()),
+      base::Bind(&JsonPrefStore::RegisterOnNextSuccessfulWriteReply,
+                 unprotected_pref_store->AsWeakPtr()),
+      base::Bind(&JsonPrefStore::RegisterOnNextSuccessfulWriteReply,
+                 protected_pref_store->AsWeakPtr()),
+      CreatePrefHashStore(config->seed, config->legacy_device_id, false),
+      CreatePrefHashStore(config->seed, config->legacy_device_id, true),
+      raw_unprotected_pref_hash_filter, raw_protected_pref_hash_filter);
+
+  return new SegregatedPrefStore(unprotected_pref_store, protected_pref_store,
+                                 protected_pref_names);
+}
+
+}  // namespace prefs